Human In The Loop

Human-in-the-Loop Instrumentation

Instrument human intervention points to understand approval workflows and feedback.

Core Principle

HITL observability answers:

1. When did the agent request human input?
2. Why was human input needed?
3. How long did humans take to respond?
4. What was the outcome of human intervention?
5. How often do agents escalate vs. proceed autonomously?

Human Intervention Types

Approval Request

Agent requests permission before proceeding:

span.set_attribute("human.type", "approval")
span.set_attribute("human.action_requested", "execute_trade")
span.set_attribute("human.risk_level", "high")
span.set_attribute("human.auto_approve_eligible", False)

Clarification Request

Agent needs more information:

span.set_attribute("human.type", "clarification")
span.set_attribute("human.question", "Which account to use?")
span.set_attribute("human.options_provided", 3)

Error Escalation

Agent encountered unrecoverable error:

span.set_attribute("human.type", "escalation")
span.set_attribute("human.reason", "tool_failure")
span.set_attribute("human.error_type", "APIError")
span.set_attribute("human.retry_count_before_escalation", 3)

Feedback Request

Agent requests quality feedback:

span.set_attribute("human.type", "feedback")
span.set_attribute("human.feedback_on", "response_quality")
span.set_attribute("human.optional", True)

Request Span Attributes

# Request metadata (P0)
span.set_attribute("human.request_id", str(uuid4()))
span.set_attribute("human.type", "approval")
span.set_attribute("human.agent_name", "executor")
span.set_attribute("human.timestamp", datetime.utcnow().isoformat())

# Context (P1)
span.set_attribute("human.action_summary", "Delete 50 records")
span.set_attribute("human.risk_assessment", "medium")
span.set_attribute("human.reversible", True)
span.set_attribute("human.deadline", "2024-01-15T10:00:00Z")

# Routing (P2)
span.set_attribute("human.assigned_to", "team_ops")
span.set_attribute("human.priority", "high")
span.set_attribute("human.channel", "slack")

Response Span Attributes

# Response metadata (P0)
span.set_attribute("human.response_id", str(uuid4()))
span.set_attribute("human.decision", "approved")  # approved, rejected, modified
span.set_attribute("human.responded_at", datetime.utcnow().isoformat())
span.set_attribute("human.wait_time_ms", 45000)

# Responder (P1)
span.set_attribute("human.responder_id", "user_123")  # Hashed
span.set_attribute("human.responder_role", "admin")

# Modifications (if applicable)
span.set_attribute("human.modified", True)
span.set_attribute("human.modification_summary", "Reduced to 25 records")

# Feedback (if applicable)
span.set_attribute("human.feedback_score", 4)  # 1-5
span.set_attribute("human.feedback_comment_length", 150)

Timing Metrics

Track wait times for SLA monitoring:

# Request-to-response timing
span.set_attribute("human.time_to_response_ms", 45000)
span.set_attribute("human.time_to_first_view_ms", 12000)
span.set_attribute("human.sla_target_ms", 300000)  # 5 min SLA
span.set_attribute("human.sla_met", True)

# Queue metrics
span.set_attribute("human.queue_position", 3)
span.set_attribute("human.queue_wait_ms", 30000)

Workflow Patterns

Synchronous Approval

Agent blocks until human responds:

with tracer.start_span("human.approval_sync") as span:
    span.set_attribute("human.blocking", True)
    span.set_attribute("human.timeout_ms", 300000)

    request_id = request_approval(action)
    decision = wait_for_decision(request_id, timeout=300)

    span.set_attribute("human.decision", decision)
    span.set_attribute("human.wait_time_ms", elapsed)

Asynchronous Approval

Agent proceeds with other work:

with tracer.start_span("human.approval_async") as span:
    span.set_attribute("human.blocking", False)
    span.set_attribute("human.callback_url", callback_url)

    request_id = request_approval_async(action, callback_url)
    span.set_attribute("human.request_id", request_id)
    # Agent continues with other work

Auto-Approval with Override

Low-risk actions auto-approve:

with tracer.start_span("human.auto_approval") as span:
    risk = assess_risk(action)
    span.set_attribute("human.risk_score", risk)

    if risk < RISK_THRESHOLD:
        span.set_attribute("human.auto_approved", True)
        span.set_attribute("human.override_available", True)
        proceed(action)
    else:
        span.set_attribute("human.auto_approved", False)
        request_approval(action)

Aggregation Metrics

Track patterns over time:

# Per-agent metrics
span.set_attribute("agent.human_requests_today", 15)
span.set_attribute("agent.approval_rate", 0.85)
span.set_attribute("agent.avg_wait_time_ms", 35000)

# Per-workflow metrics
span.set_attribute("workflow.human_touchpoints", 3)
span.set_attribute("workflow.autonomous_steps", 12)
span.set_attribute("workflow.automation_rate", 0.80)

Framework Integration

LangGraph Human Node

from langgraph.prebuilt import create_react_agent
from langfuse.decorators import observe

@observe(name="human.interrupt")
def human_approval_node(state):
    span = get_current_span()
    span.set_attribute("human.type", "approval")
    span.set_attribute("human.state_summary", summarize(state))

    # Request human input
    decision = interrupt(state)

    span.set_attribute("human.decision", decision)
    return {"approved": decision == "approve"}

CrewAI Human Input

from crewai import Agent
from langfuse.decorators import observe

@observe(name="human.feedback")
def request_human_feedback(output: str) -> str:
    span = get_current_span()
    span.set_attribute("human.type", "feedback")

    feedback = human_input(f"Review: {output}")

    span.set_attribute("human.feedback_length", len(feedback))
    return feedback

Anti-Patterns

• Missing wait time tracking (SLA blindness)
• No decision logging (can't audit)
• Blocking without timeout (hung agents)
• No escalation tracking (hidden failures)

Related Skills

• error-retry-tracking - Escalation patterns
• evaluation-quality - Feedback integration